i) A motorcycle moving with a speed of 5 m/s is subjected to an acceleration of 0.2m/S2 calculate the speed of motorcycle after 10 second and the distance travelled in this time. ii) A bus running at a speed of 18km/hr is stopped in 2.5 sec by applying brakes. Calculate the retardation produced.

1) Given that

The initial speed of car=u= 5 m/s

Acceleration =a=0.2m/s2

Time=t=10s

We need to calculate the distance

We know that

v = u + at

= 5 + 0.2×10

= 5+2

= 7 m/s

s = ut + 1/2at²

= (5×10) + (1/2)×(2/10)×(10×10)

= 50 + 10

= 60 m

Final speed = 7 m/s

Distance traveled in 10 seconds = 60 m

2) Given that

Initial velocity = 18 km/h

We will express it in m/s

So Initial velocity = 18 km/h= 18×5/18 m/sec= 5 m/sec

The final velocity = zero

Acceleration = change in velocity/time
= ( final velocity – intial velocity)/time
= ( 0 – 5)/2.5 = -2 m/s²

so, retardation = 2m/s²

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